This porous silicon sensor device for rapid gas detection is an innovative approach to chemical sensing technology. It was designed to make significant improvements in the operation of gas sensors, sensor arrays, catalysts, and micro-reactors. The device’s interfaces are novel, rational, and inexpensively implemented. They are also tailored to target specifications and can operate across a wide range of temperatures and pressures.
Georgia Tech’s device has been shown to remain stable despite the presence of water vapor. The matrix’s sensitivity is high (near parts per billion)—producing analyte selectivity in mixed analyte environments—and its response rate averages 2 seconds. Additionally, the sensor’s energy-efficient power requirements demand less than a traditional watch battery.
In sharp contrast to typical metal-oxide sensors, this technology manages a range of atmospheric temperatures, from room temperature to elevated temperatures as great as 200 °C with an insensitivity to temperature drift.
- Rapid response: Provides results for gas detection through the nanostructure island sites within 2 seconds on average
- Heat resistant: Works effectively in temperatures ranging from room temperature to 200 °C
- Easily modified: Provides a range of sensitivities for a broad range of gases for use in many commercial industries
- Industrial combustion environments
- Automotive emissions testing
- Air quality monitoring
- Medical testing applications for asthmatic monitoring or to detect transplant rejections
- Law enforcement identification of gases in suspected methamphetamines labs
Current commercial gas sensing technologies are limited by size, range of analyte sensitivity, and heat endurance. The majority of market-available devices in this field are siloed according to their detection methodology—either electrical or other (e.g., optic, acoustic). Georgia Tech’s innovative porous silicon sensor and many of the standard industrial sensors fall into an electrical subcategory labeled “metal-oxide semiconductors.” The demand for gas sensors with flexibility to cover many analytes with high sensitivity yet maintain low energy consumption and a compact design has not been met by manufacturers. This invention meets these demands while also providing rapid response with the possibility of reversibility and delivering results effectively in a wide variety of temperatures regardless of whether water vapor is present.
How It Works
Georgia Tech researchers developed a unique etch process to create a nanoparticle deposited micro-porous array with distinct, electronically independent detection centers. The porous silicon (pSi) sensor leverages hard and soft acid-base (HSAB) interactions to dictate a variable conductometric response.
Unlike surface coating techniques, this innovation controls the concentration of detection centers to produce the optimum matrix of enhanced sensor responses. The nanostructure island sites within each micro-pore force a dominant distinct analyte-interface physical adsorption (rather than chemisorption), resulting in a conductometric response with minimal power required. The metal-oxide decorated semiconductor interface can be easily functionalized to create an enhanced scope of interactive nanoparticle-semiconductor sites with a range of sensitivities for a wide variety of gases. Furthermore, nitration of the interface produces a high degree of hydrophobicity. The interface is formattable for sensor arrays and generated distinct response matrices.